A 10-yr-old boy visited Minoh City Hospital complaining of gross hematuria. Laboratory investigations revealed hypercalcemia, hypophosphatemia, and elevated serum levels of parathyroid hormone. A stone was found in the right ureter with drip infusion pyelography. A parathyroid adenoma was successfully diagnosed with computed tomography, ultrasonography, and methoxy-2-isobutyl isonitrile (MIBI) scintigraphy. Multiple endocrine neoplasia was ruled out by normal results of endocrine laboratory examinations. Extracorporeal shock wave lithotripsy was performed to treat the urolithiasis, and the parathyroid adenoma was surgically removed. Primary hyperparathyroidism is rare in childhood; however, this case suggests that gross hematuria is an important sign of hyperparathyroidism.